/*
 * Copyright 2013-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.alibaba.cloud.sentinel.datasource.converter;

import com.alibaba.csp.sentinel.datasource.Converter;
import com.alibaba.csp.sentinel.slots.block.authority.AuthorityRule;
import com.alibaba.csp.sentinel.slots.block.degrade.DegradeRule;
import com.alibaba.csp.sentinel.slots.block.flow.FlowRule;
import com.alibaba.csp.sentinel.slots.block.flow.param.ParamFlowRule;
import com.alibaba.csp.sentinel.slots.system.SystemRule;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.StringUtils;

import java.io.IOException;
import java.util.*;
/**
 <p>
 * Convert sentinel rules for json or xml array Using strict mode to parse json or xml.
 * @author <a href="mailto:fangjian0423@gmail.com">Jim</a>
 * @see FlowRule
 * @see DegradeRule
 * @see SystemRule
 * @see AuthorityRule
 * @see ParamFlowRule
 * @see ObjectMapper
 </p>
 * 儒猿课堂: http://www.ruyuan2020.com
 * @Author zhonghuashishan
 * @Remark 有问题直接联系客服VX: ruyuan-1111 ，源码-笔记-技术交流群
 * @Version 1.0
 **/
public abstract class SentinelConverter<T extends Object>
        implements Converter<String, Collection<Object>> {

    private static final Logger log = LoggerFactory.getLogger(SentinelConverter.class);

    private final ObjectMapper objectMapper;

    private final Class<T> ruleClass;

    public SentinelConverter(ObjectMapper objectMapper, Class<T> ruleClass) {
        this.objectMapper = objectMapper;
        this.ruleClass = ruleClass;
    }

    @Override
    public Collection<Object> convert(String source) {
        Collection<Object> ruleCollection;

        // hard code
        if (ruleClass == FlowRule.class || ruleClass == DegradeRule.class
                || ruleClass == SystemRule.class || ruleClass == AuthorityRule.class
                || ruleClass == ParamFlowRule.class) {
            ruleCollection = new ArrayList<>();
        } else {
            ruleCollection = new HashSet<>();
        }

        if (StringUtils.isEmpty(source)) {
            log.warn("converter can not convert rules because source is empty");
            return ruleCollection;
        }
        try {
            List sourceArray = objectMapper.readValue(source,
                    new TypeReference<List<HashMap>>() {
                    });

            for (Object obj : sourceArray) {
                try {

                    Object jsonObj = null;
                    if (ruleClass == AuthorityRule.class
                            || ruleClass == ParamFlowRule.class) {
                        HashMap hashMap = (HashMap) obj;
                        LinkedHashMap rules = (LinkedHashMap) hashMap.get("rule");
                        jsonObj = rules;
                    } else {
                        jsonObj = obj;
                    }

                    String item = objectMapper.writeValueAsString(jsonObj);
                    Optional.ofNullable(convertRule(item))
                            .ifPresent(convertRule -> ruleCollection.add(convertRule));
                } catch (IOException e) {
                    log.error("sentinel rule convert error: " + e.getMessage(), e);
                    throw new IllegalArgumentException(
                            "sentinel rule convert error: " + e.getMessage(), e);
                }
            }
        } catch (Exception e) {
            if (e instanceof RuntimeException) {
                throw (RuntimeException) e;
            } else {
                throw new RuntimeException("convert error: " + e.getMessage(), e);
            }
        }
        return ruleCollection;
    }

    private Object convertRule(String ruleStr) throws IOException {
        return objectMapper.readValue(ruleStr, ruleClass);
    }

}
